假设我有一个垂直线性布局:
[v1]
[v2]
默认情况下，v1已经可见= GONE。我想用一个展开动画显示v1，同时下推v2。
我是这样做的:
Animation a = new Animation()
{
int initialHeight;
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
final int newHeight = (int)(initialHeight * interpolatedTime);
v.getLayoutParams().height = newHeight;
v.requestLayout();
}
@Override
public void initialize(int width, int height, int parentWidth, int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
initialHeight = height;
}
@Override
public boolean willChangeBounds() {
return true;
}
};
但是用这个解决方案，当动画开始时我有一个眨眼。我认为这是由于v1在应用动画之前显示全尺寸。
用javascript，这是一行jQuery!android有什么简单的方法吗?
public static void expand(final View v, int duration, int targetHeight) {
v.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
v.getLayoutParams().height = 0;
v.setVisibility(View.VISIBLE);
ValueAnimator valueAnimator = ValueAnimator.ofInt(0, targetHeight);
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (int) animation.getAnimatedValue();
v.requestLayout();
}
});
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.setDuration(duration);
valueAnimator.start();
}
public static void collapse(final View v, int duration, int targetHeight) {
ValueAnimator valueAnimator = ValueAnimator.ofInt(0, targetHeight);
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (int) animation.getAnimatedValue();
v.requestLayout();
}
});
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.setDuration(duration);
valueAnimator.start();
}
这是一个片段，我用来调整一个视图(线性布局)的宽度与动画。
代码应该根据目标大小进行扩展或收缩。如果你想要一个fill_parent宽度，你必须在将标志设置为true时将父类. getmeasuredwidth作为目标宽度。
希望它能帮助到你们中的一些人。
public class WidthResizeAnimation extends Animation {
int targetWidth;
int originaltWidth;
View view;
boolean expand;
int newWidth = 0;
boolean fillParent;
public WidthResizeAnimation(View view, int targetWidth, boolean fillParent) {
this.view = view;
this.originaltWidth = this.view.getMeasuredWidth();
this.targetWidth = targetWidth;
newWidth = originaltWidth;
if (originaltWidth > targetWidth) {
expand = false;
} else {
expand = true;
}
this.fillParent = fillParent;
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
if (expand && newWidth < targetWidth) {
newWidth = (int) (newWidth + (targetWidth - newWidth) * interpolatedTime);
}
if (!expand && newWidth > targetWidth) {
newWidth = (int) (newWidth - (newWidth - targetWidth) * interpolatedTime);
}
if (fillParent && interpolatedTime == 1.0) {
view.getLayoutParams().width = -1;
} else {
view.getLayoutParams().width = newWidth;
}
view.requestLayout();
}
@Override
public void initialize(int width, int height, int parentWidth, int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
}
@Override
public boolean willChangeBounds() {
return true;
}
}
我改编了汤姆·埃斯特兹(Tom Esterez)目前接受的答案，这个答案有效，但动画起伏不定，不太流畅。我的解决方案基本上是用ValueAnimator替换动画，它可以与你选择的Interpolator相匹配，以实现各种效果，如超调、反弹、加速等。
这个解决方案非常适用于具有动态高度的视图(即使用WRAP_CONTENT)，因为它首先测量实际所需的高度，然后动画到该高度。
public static void expand(final View v) {
v.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
final int targetHeight = v.getMeasuredHeight();
// Older versions of android (pre API 21) cancel animations for views with a height of 0.
v.getLayoutParams().height = 1;
v.setVisibility(View.VISIBLE);
ValueAnimator va = ValueAnimator.ofInt(1, targetHeight);
va.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (Integer) animation.getAnimatedValue();
v.requestLayout();
}
});
va.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationEnd(Animator animation) {
v.getLayoutParams().height = ViewGroup.LayoutParams.WRAP_CONTENT;
}
@Override public void onAnimationStart(Animator animation) {}
@Override public void onAnimationCancel(Animator animation) {}
@Override public void onAnimationRepeat(Animator animation) {}
});
va.setDuration(300);
va.setInterpolator(new OvershootInterpolator());
va.start();
}
public static void collapse(final View v) {
final int initialHeight = v.getMeasuredHeight();
ValueAnimator va = ValueAnimator.ofInt(initialHeight, 0);
va.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (Integer) animation.getAnimatedValue();
v.requestLayout();
}
});
va.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationEnd(Animator animation) {
v.setVisibility(View.GONE);
}
@Override public void onAnimationStart(Animator animation) {}
@Override public void onAnimationCancel(Animator animation) {}
@Override public void onAnimationRepeat(Animator animation) {}
});
va.setDuration(300);
va.setInterpolator(new DecelerateInterpolator());
va.start();
}
然后你只需调用expand(myView);或崩溃(myView);。
利用Kotlin扩展函数这是测试和最短的答案
在任何视图上调用animateVisibility(expand/collapse)即可。
fun View.animateVisibility(setVisible: Boolean) {
if (setVisible) expand(this) else collapse(this)
}
private fun expand(view: View) {
view.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)
val initialHeight = 0
val targetHeight = view.measuredHeight
// Older versions of Android (pre API 21) cancel animations for views with a height of 0.
//v.getLayoutParams().height = 1;
view.layoutParams.height = 0
view.visibility = View.VISIBLE
animateView(view, initialHeight, targetHeight)
}
private fun collapse(view: View) {
val initialHeight = view.measuredHeight
val targetHeight = 0
animateView(view, initialHeight, targetHeight)
}
private fun animateView(v: View, initialHeight: Int, targetHeight: Int) {
val valueAnimator = ValueAnimator.ofInt(initialHeight, targetHeight)
valueAnimator.addUpdateListener { animation ->
v.layoutParams.height = animation.animatedValue as Int
v.requestLayout()
}
valueAnimator.addListener(object : Animator.AnimatorListener {
override fun onAnimationEnd(animation: Animator) {
v.layoutParams.height = targetHeight
}
override fun onAnimationStart(animation: Animator) {}
override fun onAnimationCancel(animation: Animator) {}
override fun onAnimationRepeat(animation: Animator) {}
})
valueAnimator.duration = 300
valueAnimator.interpolator = DecelerateInterpolator()
valueAnimator.start()
}
根据@Tom Esterez和@Seth Nelson的解决方案，我对它们进行了简化。与原始解决方案一样，它不依赖于开发人员选项(动画设置)。
private void resizeWithAnimation(final View view, int duration, final int targetHeight) {
final int initialHeight = view.getMeasuredHeight();
final int distance = targetHeight - initialHeight;
view.setVisibility(View.VISIBLE);
Animation a = new Animation() {
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
if (interpolatedTime == 1 && targetHeight == 0) {
view.setVisibility(View.GONE);
}
view.getLayoutParams().height = (int) (initialHeight + distance * interpolatedTime);
view.requestLayout();
}
@Override
public boolean willChangeBounds() {
return true;
}
};
a.setDuration(duration);
view.startAnimation(a);
}
